project-base/server-skynet-source-3rd-jemalloc
2
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Ehooks: Add a "zero" ehook.

Browse Source 
This is the first API expansion.  It lets the hooks pick where and how to purge
within themselves.
This commit is contained in:
David Goldblatt 2019-12-04 17:55:24 -08:00 committed by David Goldblatt
parent d0f187ad3b
commit 4b2e5ee8b9
3 changed files with 48 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
include/jemalloc/internal/ehooks.h
View File

@ -43,6 +43,7 @@ bool ehooks_default_purge_forced_impl(void *addr, size_t offset, size_t length);
#endif
bool ehooks_default_split_impl();
bool ehooks_default_merge_impl(void *addr_a, void *addr_b);
void ehooks_default_zero_impl(void *addr, size_t size);
/*
* We don't officially support reentrancy from wtihin the extent hooks. But
@ -261,4 +262,21 @@ ehooks_merge(tsdn_t *tsdn, ehooks_t *ehooks, void *addr_a, size_t size_a,
}
}
static inline void
ehooks_zero(tsdn_t *tsdn, ehooks_t *ehooks, void *addr, size_t size,
unsigned arena_ind) {
extent_hooks_t *extent_hooks = ehooks_get_extent_hooks_ptr(ehooks);
if (extent_hooks == &ehooks_default_extent_hooks) {
ehooks_default_zero_impl(addr, size);
} else {
/*
* It would be correct to try using the user-provided purge
* hooks (since they are required to have zeroed the extent if
* they indicate success), but we don't necessarily know their
* cost. We'll be conservative and use memset.
*/
memset(addr, 0, size);
}
}
#endif /* JEMALLOC_INTERNAL_EHOOKS_H */

17
src/ehooks.c
View File

@ -209,6 +209,23 @@ ehooks_default_merge(extent_hooks_t *extent_hooks, void *addr_a, size_t size_a,
return ehooks_default_merge_impl(addr_a, addr_b);
}
void
ehooks_default_zero_impl(void *addr, size_t size) {
/*
* By default, we try to zero out memory using OS-provided demand-zeroed
* pages. If the user has specifically requested hugepages, though, we
* don't want to purge in the middle of a hugepage (which would break it
* up), so we act conservatively and use memset.
*/
bool needs_memset = true;
if (opt_thp != thp_mode_always) {
needs_memset = pages_purge_forced(addr, size);
}
if (needs_memset) {
memset(addr, 0, size);
}
}
const extent_hooks_t ehooks_default_extent_hooks = {
ehooks_default_alloc,
ehooks_default_dalloc,

38
src/extent2.c
View File

@ -758,17 +758,6 @@ extent_recycle_split(tsdn_t *tsdn, arena_t *arena, ehooks_t *ehooks,
unreachable();
}
static bool
extent_need_manual_zero(arena_t *arena) {
/*
* Need to manually zero the extent on repopulating if either; 1) non
* default extent hooks installed (in which case the purge semantics may
* change); or 2) transparent huge pages enabled.
*/
return (!ehooks_are_default(arena_get_ehooks(arena)) ||
(opt_thp == thp_mode_always));
}
/*
* Tries to satisfy the given allocation request by reusing one of the extents
* in the given eset_t.
@ -807,9 +796,6 @@ extent_recycle(tsdn_t *tsdn, arena_t *arena, ehooks_t *ehooks, eset_t *eset,
growing_retained);
return NULL;
}
if (!extent_need_manual_zero(arena)) {
extent_zeroed_set(extent, true);
}
}
if (extent_committed_get(extent)) {
@ -832,11 +818,10 @@ extent_recycle(tsdn_t *tsdn, arena_t *arena, ehooks_t *ehooks, eset_t *eset,
void *addr = extent_base_get(extent);
if (!extent_zeroed_get(extent)) {
size_t size = extent_size_get(extent);
if (extent_need_manual_zero(arena) ||
pages_purge_forced(addr, size)) {
memset(addr, 0, size);
}
} else if (config_debug) {
ehooks_zero(tsdn, ehooks, addr, size,
arena_ind_get(arena));
}
if (config_debug) {
size_t *p = (size_t *)(uintptr_t)addr;
/* Check the first page only. */
for (size_t i = 0; i < PAGE / sizeof(size_t); i++) {
@ -960,8 +945,14 @@ extent_grow_retained(tsdn_t *tsdn, arena_t *arena, ehooks_t *ehooks,
&arena->eset_retained, extent, true);
goto label_err;
}
if (!extent_need_manual_zero(arena)) {
extent_zeroed_set(extent, true);
/* A successful commit should return zeroed memory. */
if (config_debug) {
void *addr = extent_addr_get(extent);
size_t *p = (size_t *)(uintptr_t)addr;
/* Check the first page only. */
for (size_t i = 0; i < PAGE / sizeof(size_t); i++) {
assert(p[i] == 0);
}
}
}
@ -996,10 +987,7 @@ extent_grow_retained(tsdn_t *tsdn, arena_t *arena, ehooks_t *ehooks,
if (*zero && !extent_zeroed_get(extent)) {
void *addr = extent_base_get(extent);
size_t size = extent_size_get(extent);
if (extent_need_manual_zero(arena) ||
pages_purge_forced(addr, size)) {
memset(addr, 0, size);
}
ehooks_zero(tsdn, ehooks, addr, size, arena_ind_get(arena));
}
return extent;